
<em><u>The Rutherford model shows that an atom is mostly empty space, with electrons orbiting a fixed, positively charged nucleus in set, predictable paths.</u></em>
Six elemental gases are composed of such exceptionally stable atoms that they almost never react with other elements. They are the gases that make up Group 0 (the rightmost column) of the periodic table: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn).
The subscript in a chemical reaction cannot be changed. Its written like this:-
Ca₆
That means Ca = 6